Open Access

Jörn Adamczewski-Musch, Geydar Agakishiev, Oliver Werner Arnold, Ermias T. Atomssa, Claudia Behnke, Jia-Chii Berger-Chen, Jacek Biernat, Alberto Blanco, Christoph Blume, Michael Böhmer, Paula Bordalo, Sergey P. Chernenko, Christina Anna Deveaux, Adrian Dybczak, Eliane Epple, Laura Fabbietti, Oleg Fateev, Paulo Fonte, Celso Franco, Jürgen Friese, Ingo Fröhlich, Tetyana Galatyuk, Juan A. Garzón, Roman Gernhäuser, Katharina Gill, Marina Golubeva, Fedor Guber, Malgorzata Gumberidze, Szymon Harabasz, Thierry Hennino, Stanislav Hlaváč, Claudia Höhne, Romain Holzmann, Alexander P. Ierusalimov, Alexander Ivashkin, Martin Jurkovič, Burkhard Kämpfer, Tatiana L. Karavicheva, Behruz Kardan, Ilse Koenig, W. Koenig, Burkhard W. Kolb, Grzegorz Korcyl, Georgy Kornakov, Roland Kotte, Antonin Krása, Erik Krebs, Hubert Kuc, Andrej Kugler, Tobias Kunz, Alexander Kurepin, Aleksey K. Kurilkin, Pavel Kurilkin, Vladimir P. Ladygin, Rafał Tomasz Lalik, Kirill Lapidus, Alexei Lebedev, Luis Alberto Vieira Lopes, Manuel Lorenz, Tariq Mahmoud, Ludwig W. Maier, Steffen Maurus, Alessio Mangiarotti, Jochen Markert, Volker Metag, Jan Michel, Christian Müntz, Robert Helmut Münzer, Lothar Naumann, Marek Palka, Yannis Parpottas, Vladimir Pechenov, Olga Pechenova, Vlasios Petousis, Jerzy Pietraszko, Witold Przygoda, S. Ramos, Béatrice Ramstein, Laura Rehnisch, Andrey Reshetin, Adrian Rost, Anar Rustamov, Alexander Sadovsky, Piotr Salabura, Timo Scheib, Korbinian Schmidt-Sommerfeld, Heidi Schuldes, Patrick Sellheim, Johannes Stephan Siebenson, L. Silva, Yuri G. Sobolev, Stefano Spataro, Herbert Ströbele, Joachim Stroth, Paweł Strzempek, C. Sturm, Ondřej Svoboda, Attilio Tarantola Peloni, Khaled Teilab, Pavel Tlustý, Michael Traxler, Haralabos Tsertos, Taras A. Vasiliev, Vladimir Wagner, Christian Wendisch, Joana Wirth, Jörn Wüstenfeld, Yuri V. Zanevsky, Peter W. Zumbruch

• The production of Σ0 baryons in the nuclear reaction p (3.5 GeV) + Nb (corresponding to sNN=3.18 GeV) is studied with the detector set-up HADES at GSI, Darmstadt. Σ0s were identified via the decay Σ0→Λγ with subsequent decays Λ→pπ− in coincidence with a e+e− pair from either external (γ→e+e−) or internal (Dalitz decay γ⁎→e+e−) gamma conversions. The differential Σ0 cross section integrated over the detector acceptance, i.e. the rapidity interval 0.5<y<1.1, has been extracted as ΔσΣ0=2.3±(0.2)stat±(−0.6+0.6)sys±(0.2)norm mb, yielding the inclusive production cross section in full phase space σΣ0total=5.8±(0.5)stat±(−1.4+1.4)sys±(0.6)norm±(1.7)extrapol mb by averaging over different extrapolation methods. The Λall/Σ0 ratio within the HADES acceptance is equal to 2.3±(0.2)stat±(−0.6+0.6)sys. The obtained rapidity and momentum distributions are compared to transport model calculations. The Σ0 yield agrees with the statistical model of particle production in nuclear reactions. Keywords: Hyperons, Strangeness, Proton, Nucleus.